| One Digit | Two Digits | Up/Down Counter | Three Digits | Shuffle Score Board |
Displays, to buy or not to buy ?
You can buy large displays for about (US) $10.00 each or more which require only 20 mA per segments . Since I recommend that only 10 mA per segment be allowed we are looking at a total current for two displays of about 140 mA plus the current for the circuit boards and if this is the way you chose to go you can then use Common Cathode displays and eliminate the use of the ULN2003/MC1413 and connect the display directly to the Rs resistors.
Very large 20cm ( 7.8" ) Common Anode LED Displays in Kit form can be purchased HERE for $39.95 US
On the other hand making your own displays with a bunch of matched LED could be fun and save you quite a few bucks . Because they would require more current the ULN2003/MC1413 will be needed as well as a higher source of current .
Displays, making your own
Making large displays is not difficult , you can use two PCB layout side by side or wire each LEDs as shown on a perforated board large enought to accomodate two display side by side . The Displays will measure approx. 2" high and each segment will consist of four LEDs charing a current source controlled by Rs . As the drawing shows each segment will require 10mA times 4 or 40mA times 7 segments or 280 mA per display . So for two displays we will require a current source of 560 mA plus the circuits current . So we can safely settle on a 15 volts transformer rated at 1 amp for a regulated voltage output of 12 volts for the power supply for each two digits scoring board.
Use the brightest LED you can find , round or rectangular , you will need a total of 28 LEDs per display . Two different colours for each scoring board , like red and green plus a few spare LEDs for replacement in case some are or go bad .
Once you have completed the displays , a plastic filter of the same colour will be needed to cover the size of the two displays . These filter (1/8' thickness) can readily be purchased and cut to size from scrap by your local plastic supplier at a very little cost .
Power Supply
A schematic of a power supply is shown above . The transformer rating is for one two digits scoring board . It may be judged more economical to use only one transformer for both scoring board with an increased current rating of 2 amps , but we run into the regulator problem where it is only rated for 1.5 amps . On the other hand the system will tolerate and unregulated supply , so we can use a single transformer rated at 12 volts/2 amps and a 3 amps rectifier bridge filtered by a large capacitor of 1000uF/25 volts .
Or as previously stated , use two lower rated transformers with regulators for each scoring board , the AC supply source to each or all transformers should be controlled by an on/off switch .General Assembly
Shown below is a suggested general assembly of the scoring system . The scoring board assembly should be put into an enclosure of your choice and mounted as shown by a supporting pipe or tube into which all the wiring can be routed to the shuffle board table power supply , control buttons and set-up switch . The power supply for safety should also be enclosed into a box with adequate ventilation and mounted on the side or under the table alongs with the ON/OFF switches .
Nice large coloured game push buttons are available for a very reasonable price and could be mounted into a small box and secured to the side of the table flush with the table top .
May this project bring you great satisfaction , I tried very hard to include all the necessary information to make this project as easy as possible . A visit to the following sites will surely give you more insight and spark your imagination .
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One Digit Two Digits Up/Down Counter Three Digits Shuffle Score Board
